﻿<p>This enumeration defines the flow direction at a distribution port.</p>

<ul>
<li>For pipe-based ports, the direction is the physical flow direction.</li>
<li>For duct-based ports, the direction is the physical flow direction.</li>
li>For cable-based ports carrying electric power (circuits containing hot, neutral, ground), the direction is from the origination of power (from a distribution board to protective devices to switches to fixtures).  For cable-based ports carrying communication signals, the direction originates from where the signal is shaped, such as a sensor.  For communicaton networks, the direction originates from the up-level network host, such as a router (having <em>SOURCE</em> ports) hosting multiple computers (having <em>SINK</em> ports).</li>

<blockquote class="history">
HISTORY&nbsp; New enumeration in IFC2.0.
</blockquote>